The qualification competition for the 1990 FIFA World Cup was a series of tournaments organised by the six FIFAconfederations. Each confederation — the AFC (Asia), CAF (Africa), CONCACAF (North America), CONMEBOL (South America), OFC (Oceania), and UEFA (Europe) — was allocated a certain number of the 24 places at the tournament. A total of 116 teams entered the competition, with Italy, as the host, and Argentina, as the holders, qualifying for the final tournament automatically.

The first qualification match was played on 17 April 1988 and qualification concluded on 19 November 1989. A total of 735 goals were scored in the 314 qualifying matches (an average of 2.34 per match).

At the close of entries on 30 September 1987, a total of 116 football associations had entered the 1990 World Cup. This entry figure was five lower than those who originally entered the previous tournament, a then-World Cup record of 121 entries.

Three entries were rejected by FIFA: Belize, Mauritius and Mozambique due to their outstanding financial debts, taking the number of accepted teams down to 113. With both the hosts and holders qualifying automatically for the finals, 111 nations were therefore scheduled to compete in the qualifying competitions. Gabon, Oman and Pakistan were making their first appearance in the World Cup.

Seven teams withdrew during the qualifying process without playing a match: Bahrain, India, Lesotho, Maldives, Rwanda, South Yemen and Togo. Mexico were disqualified from the CONCACAF qualifying tournament before playing a game for fielding overage players in the qualifying stages for the 1988 Olympic Games. Libya withdrew during the CAF group stage, but had already (successfully) played in the first round. Therefore the total number of teams playing at least one fixture during the 1990 World Cup competition was 105 (103 during qualifying).

The qualification process commenced in April 1988 and was completed in November 1989. The draw for all qualifying groups and opening round ties in the six confederations was held in Zürich, Switzerland on 12 December 1987.

The CAF qualification process began with a preliminary round between June and November 1988, which eliminated eight nations.

These eight nations were joined in the second round by the eight highest-ranked African nations, which had received a bye in the first round. These sixteen teams were placed in four groups of four teams, with the group winners advancing to the final round. The four group winners of these groups were paired together into two knockout ties played during October and November 1989. The winners of these two-legged ties qualified for the World Cup finals.

The group stage draw divided the teams into six groups, which were played from January to July 1989, from which the six group winners advanced to the final group stage. The final group stage saw the six remaining teams play each other once during a sixteen day tournament based in Singapore in October 1989. The two top teams qualified for the World Cup finals.

The European qualification games started in May 1988 and ended in November 1989. Seven groups were drawn in total: Four of five teams and three groups of four contested the European qualifying competition. As a result, the seven group-winners qualified, while the runners-up in the groups containing five teams also qualified directly. The runners-up in the three groups containing only four teams were ranked, with the two teams with the best records also qualifying. The weakest runner-up missed out (Denmark).

The 1989 CONCACAF Championship also served as the qualifying process for the 1990 FIFA World Cup. The Championship consisted of a two-round qualification process, with the ten lowest-ranked CONCACAF teams beginning in the first round. The five teams successfully winning their two-legged ties were joined by the five highest ranked CONCACAF teams in the second round, which again consisted of teams being drawn into two-legged ties. The five victorious teams contested the final tournament of the 1989 Championship, which took the form of a group with teams playing each other on a home-and-away basis. The eventual CONCACAF champions and runners-up qualified for the World Cup finals.

(5 teams competing for 0 or 1 berth; a play-off against CONMEBOL determines which confederation gets the extra berth)

The qualification process began in November 1988 with the strongest two OFC teams facing the two other OFC entrants in two-legged ties. The two winners advanced to a final group where they were joined by non-OFC members Israel who were allocated to this zone for the qualification process. The three teams played each other on a home-and-away basis with the team finishing top of the group advancing to a final play-off against the third best South American team for a World Cup berth.

(9 teams competing for 3 or 4 berths; a play-off against OFC determines which confederation gets the extra berth, with Argentina also qualifying automatically as World Cup holders)

The CONMEBOL qualification process featured three groups of three teams being drawn to play on a home and away basis, with matches played from July to September 1989. The records of the three group winners were ranked, with the two best teams qualifying directly for the World Cup finals; the group winner with the weakest record advanced to a play–off against the winner of the OFC zone.

There was one inter-confederation play-off to determine the final qualification spot for the 1990 FIFA World Cup finals. The play-off was contested by the CONMEBOL group winners with the weakest record and the winner of the OFC zone.

On 12 August 1989, Samuel Okwaraji collapsed and died whilst playing for Nigeria in their qualifying match against Angola, ten minutes before the end.

One of the most bizarre incidents in World Cup history occurred on 3 September 1989. During the Brazil vs Chile CONMEBOL qualifying match in Rio de Janeiro. Chile needed victory to retain any hope of qualification, but trailed 0–1 to Brazil. Around twenty minutes into the second half, Chilean goalkeeper Roberto "Cóndor" Rojas fell to the pitch with an apparent injury to his forehead. A firework, thrown from the stands by a Brazilian fan named Rosemary de Mello, was smouldering about some yards away. After carrying Rojas off the pitch, the Chilean players and coaches refused to return claiming conditions were not safe, and the match went unfinished. After studying video footage of the match showing that the firework had not made any contact with Rojas, FIFA awarded Brazil a 2–0 win, eliminating Chile from the 1990 World Cup. As punishment, Chile were barred from the qualifying process for the 1994 FIFA World Cup, and Roberto Rojas was banned for life (subsequently lifted in 2001), due to he starred the scandal when inflicted self a cut on his face to simulate an attack of the Brazilian fans, cheating falsely regarding the incident. Should be noted that this was the only time in the history, during Qualification processes. The incident is called the Maracanazo of the Chilean national team.

The decisive second leg of the CAF Final Round, tie between Egypt and Algeria in Cairo saw ugly scenes at its conclusion. The game was won 1–0 by Egypt, sending them to the 1990 World Cup at the expense of their opponent. After the final whistle, Algerian players and officials mobbed the referee and threw plant pots into the crowd. At the post-game conference, the Egyptian team doctor was blinded in one eye after being hit with a broken bottle thrown by an Algerian player. This was believed to be star striker Lakhdar Belloumi who was sentenced to prison for this offense, but he denied any wrongdoing and a twenty year international arrest warrant was eventually quashed in 2009. Teammates had previously testified that reserve goalkeeper Kamel Kadri was instead the culprit.